Transport processes and associated irreversibilities in droplet combustion in a convective medium
Transport processes and associated irreversibilities in droplet combustion in a convective medium
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对流介质中液滴燃烧的传输过程和相关的不可逆性
DOI：
10.1002/er.4440150708
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发表时间：
1991
影响因子：
4.6
通讯作者：
S. K. Som
中科院分区：
文献类型：
--
作者：
S. Dash;S. K. Som
本文通过数值求解载流相和液滴相的热量、质量和动量守恒方程，建立了热气体包围的液滴作匀速自由流运动的燃烧数学模型。燃料蒸气和氧化剂之间的气相化学反应被假定为单步和不可逆的。点火现象通过在载波相位中的不同位置处的温度/时间历史中的温度的突然上升来识别。为了确定过程的不可逆性，熵产生的瞬时速率及其随时间的变化已被确定从熵守恒方程的气相和液相的同时数值解。研究了初始雷诺数Rei、自由流与初始温度之比T∞和环境压力等输入参数对局部努塞尔数和平均努塞尔数、燃料滴燃烧寿命和液滴燃烧过程熵产率的影响。
A mathematical model of the combustion of a droplet surrounded by hot gas with a uniform free stream motion is made from the numerical solution of conservation equations of heat, mass and momentum in both the carrier and the droplet phases. The gas-phase chemical reaction between the fuel vapour and the oxidizer is assumed to be single-step and irreversible. The phenomenon of ignition is recognised by the sudden rise of temperature in the temperature/time histories at different locations in the carrier phase. To ascertain the process irreversibilities, the instantaneous rate of entropy production and its variation with time have been determined from the simultaneous numerical solution of the entropy conservation equations for both the gas and liquid phases. The relative influences of pertinent input parameters, namely the initial Reynolds number Rei, the ratio of the free stream to initial temperature T∞ and the ambient pressure on (i) the local and average Nusselt numbers, (ii) the life histories of burning fuel drops, and (iii) the entropy generation rate in the process of droplet combustion have been established.